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New Home Construction Green Ratings Systems


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Coparison of LEED & Bild It Gtreen rating systen for new home construction

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New Home Construction Green Ratings Systems

  1. 1. Architecture 160 Final Research Paper Bill Durkin New Construction “Green” rating systems A comparison of the National Leadership in Energy and Environmental Design (LEED) system and the California Green Point Rated system Buildings have a profound impact on our environment, economy, health and productivity. In the United States (US) alone, the resources used to operate commercial buildings represents about 30% of total US annual energy requirements, including 60% of domestic electricity. The building industry began to incorporate more environmentally oriented building materials, and employ different practices with significantly less negative impact on the building site, energy systems and indoor air quality. The first nationwide program, called Leadership in Energy and Environmental Design (LEED) was founded in 1993 by the US Green Building Council group. It targeted the top 25% of the nation’s “green” home builders. The group designed a rating system that enables builders to receive ‘credits’ in a number of ways for certification [2]. In California, a number of public agencies, building professionals and non-profit firms organized a state program to promote state initiatives and encourage ‘best’ sustainable practices. This effort was developed in Alameda County in 2000 with eight major home production builders collaborating to provide input and direction in the development of Green Building Guidelines. In 2005, the Guidelines were updated to expand its applicability throughout California, address changes in state building ordnances (Title 24 measures) and incorporate measures from other residential green building initiatives. Both LEED and Green Building Guidelines are similar in that both programs [1] • Require performance across different categories, as verified by a third-party rating process • Encourage builders to aim for increasingly higher levels of performance as the gain experience with green building • Serve the full range of residential new construction in California 1
  2. 2. • The certification rating verification process is managed by independent, non- profit third party agencies. Build It Green manages the Green Point Rated program, and the Davis Energy Group manages the LEED program in California. The two rating systems do differ in their scope of certification. LEED has been developed for more comprehensive programs that include existing buildings, commercial, schools, hotels and neighborhood development. Build It Green was initially formulated for new residential home construction, and is developing verification protocols for remodeling projects, and existing homes. Both LEED and Green Building Guidelines programs cover multi-family unit projects. The scope of this report will just review and focus on the verification programs for new, single family homes by the LEED and Green Building Guidelines agencies. I will compare specific components of each rating system by using design and construction phases in the renovation of the Moraga Barn in Moraga. This building was built in 1914, as a hotel, and has been completely renovated to LEED platinum standards. Although this building is a commercial building, it falls under the LEED new construction guideline, due to the extensive renovation efforts, and the need to maintain it as an historical landmark. I believe that the ‘green’ components used in the restoration can provide valid examples in this paper, to make comparative arguments about the two rating systems. Background (LEED) In the early 1990’s, an initiative began with the challenge to create a certification system that would identify and define more efficient building measures. The US Green Building Council was founded in 1993, and began the first pilot project named Leadership in Energy and Environmental Design (LEED). The committee membership included architects, realtors, building owners, attorneys and environmental and industry representatives. The group wanted to create a national rating system that would substantially reduce or eliminate negative environmental impacts in building design and construction, improve existing non-sustainable designs, and improve construction and operational practices. This initial project scope designated different rating protocols for 2
  3. 3. new construction, existing homes and commercial interiors. The LEED Rating System has now been expanded to include the following protocols, which have created a greater demand for green products and materials. The LEED rating system covers both residential and institutional (commercial, Government, public) buildings, where credits are earned for satisfying criterion, designed to address specific environmental impacts in the design, construction and operation/maintenance of buildings. Environmentally sound buildings should be healthful, durable and affordable as well. The New Construction rating system is organized into five environmental categories; 3
  4. 4. • Sustainable Sites • Water Efficiency • Energy & Atmosphere • Materials & Resources • Indoor Environmental Quality An additional category, Innovation in Design Process, addresses additional building expertise and design measures not covered under the five stated categories, or enhance an existing point attainment in the other categories [5]. Buildings that qualify for LEED rating certification must meet all prerequisites and achieve the minimum number of credits (points) required. Applicants submit their credit requests during the project design phase in order to expedite building certification, while other prerequisites can only be documented and submitted at the construction phase. Applicants must also submit specific documentation that provides verification that each specification has been completed correctly. The LEED for New Home construction 4
  5. 5. protocol has different award levels beyond the required certification credits. Levels are awarded based on the following scale – Certify 26 – 32 points Silver 33 – 38 points Gold 39 – 51 points Platinum 52 – 69 points Background (Green Point Rated) The Green Building Guidelines are administered by the Build It Green Council organization., which is a professional, membership organization whose mission is to promote healthy, durable, energy- and resource efficient buildings in California. The Guidelines were developed for several reasons • Provide local governments with a educational tool for city staff, builders and homeowners, for green building construction • To present a range of categories from which builders can choose when constructing new homes in California • To establish a regionally consistent set of guidelines for green building to help standardize building practices • To integrate varying residential initiatives in order to achieve greater simplicity and local applicability • To offer a set of guidelines developed by an independent, third party source, to maintain impartiality and standardization [3] Build It Green is the result of the 2005 merger of the Green Resource Center (est. 1999) and Bay Area Build It Green (est. 2003.) The merger combined resources of these two successful organizations and furthers the goal of transforming the California building industry to embrace green building. Bay Area Build It Green was formed in 2003 by a number of local and regionally focused public agencies, building industry professionals, manufactures, and suppliers. Its activities were focused on increasing the supply of green homes, raising consumer 5
  6. 6. awareness about the benefits of building green, and providing Bay Area consumers and residential building industry professionals a trusted source of information. The Green Resource Center started in 1999 as a joint project of the City of Berkeley, the Northern California Chapter of Architects, Designers and Planners for Social Responsibility (ADPSR), and the Sustainable Business Alliance. Initially fueled by the passion of volunteer efforts, the Green Resource Center emerged as an influential non- profit organization, operated by full-time staff and an active board of directors. The Green Resource Center was known as a trusted green building resource and has entrusted its reputation for quality, unbiased information to Build It Green. [6] These various agencies provided technical expertise and input in the creation and the update of these guidelines, the performance benchmarks in GreenPoint Rated were specifically developed to address climate and market conditions in California. In addition, several councils, including the Public Agency Council, Non-Profit Network and suppliers Network provide input for these guidelines. This holistic approach to homebuilding emphasizes quality construction, energy efficiency, improved interior air quality and more livable neighborhoods. The guidelines also stress protecting natural resources surrounding the building sites, so that the built environment can help people, communities and ecosystems thrive and prosper. And the process for updating the program over time is controlled by California decision makers and stakeholders, not by interests outside of the state. The LEED rating system national program is not tailored to specific regional conditions [6]. New homes also place greater demands on local water and energy supply and distribution systems, municipal infrastructures, roadways and transportation systems, and adjacent communities, both natural and man made. The Green Rated Program strives to reduce the impacts in these areas. The key to a successfully green built home is the careful synergy of designing and coordinating of these various measures. This whole house systems approach requires taking into account the interaction of many factors; heating, cooling needs, water use, electrical use, renewable energy systems, climate factor as, topography, and the overall well being of the home occupants. According to the Build America program, a whole house system approach can reduce the energy consumption of a new home by as much as 40%, with little or no effect in the cost of construction. 6
  7. 7. Build It Green wanted to create a more ‘accessible’ rating system to Bay Area builders than the emerging LEED standard, and combine the efforts of the various organizations that were initiating green building practices, and build an ‘easier’ rating system and process. LEED accreditation involves more costs, and process to file for credit on their various components. Green Building Guidelines Checklist The Green Point Rated (GPR) Checklist point matrix has 14 sections, and within each sub component, one can earn credits in one or more environmental ‘categories’. Each category has a total potential credit total and a required minimum number of points. A new building is considered ‘Green’ by Built It Green standards if it earns at least 50 points and meets the minimum points per category Category Total Points Minimum Community 24 NA Energy 108 30 Indoor Air Quality (IAQ)/Health 45 5 Resources 66 6 Water 47 9 Some initiatives sub-sections have potential points in two of these categories. Installing an energy efficient clothes washing machine, f or example, can earn credits in both the Energy and in Water categories (total 3 point). Like the LEED rating system, additional points are available in Innovative Design (total 20 points) Certification Examples The Canyon Construction building, located in Moraga, and referred to my many as the ‘Moraga Barn’, will be used for design & construction examples in this certification example section. The building was built in 1914, and renovated in 2006, with two design missions; to retain its historical structure, and to renovate it with a LEED platinum rating, as a working example of the high quality, working, ‘green’ construction designed and built by their company. The building is submitting 54 credits for the platinum rating. I 7
  8. 8. will use a few examples of this restoration/greening project to compare how each rating system assesses the project component. There are several assumptions to be made in the comparison of the two rating systems. LEEDS accreditation requires 26 points out of a possible 69 possible points, while the Green Point Rated system accreditation requires 50 points out a possible 300 points. While clearly the rating metric points are not immediately comparable, we can make the assumption that LEED accreditation requires 37% of possible points; the GPR system requires 16% of possible points. To simplify the comparison process, I assume that each LEED credit is calculated as roughly twice the value of the GPR credit (37% to 16%) I will use four examples to illustrate how each rating system evaluates the design/construction components for the Canyon Construction project Insulation The Moraga Barn employed two types of insulation in the remodel. Cellulose insulation is a fiber material that's sprayed into a wall's cavity during construction. This material yields higher thermal ratings due to the manner in which it fills voids and seals out airy drafts. Not only is cellulose healthy for a home, the natural chemical composition can also hinder insect infestation and is fire and mold resistant. Spray foam insulation was employed in the roof f the building to mitigate any condensation issues. The solid foam provides a barrier that eliminates any dew point issues (with a 5 ‘’ thickness, minimum). 8
  9. 9. 3.3 inch blown cellulose with 3 inch spray insulation foam in walls (R value 27) 5.5 inch spray insulation foam in roof (R-value 35) LEED, section – Energy & Atmosphere, Credit 2.2 – Insulation Insulation is subject to third party inspection for credit (1 point) and must meet Hone energy Rating system (HERS) Grade II pre-requisites, and gains credit for HERS Grade I level insulation (1 point) The Green Point Rated system, section F – Insulation, items 1, 2 and 3 :Insulate with 75% recycled content (1 point each for floor/walls and ceilings) :Insulation that is low emitting [low Volatile Organic Compounds] (1 point each for floor/walls and ceilings) : Inspection before drywall installation (1 point) Analysis Both rating systems require independent, third party verification, and reference specific standards for point accreditation. I found it very confusing to try to compare the two requirements, and obtain information on HERS grades. HVAC radiant flooring The Moraga Barn implemented a geothermal system for heating and cooling the interior of the building. The first floor had recycled granite tiles, and the second and third floors have a High Fly Ash Concrete (HVAC) slab. HFAC utilizes 50% 9
  10. 10. fly ash, to offset the cement component, thereby reducing the amount of carbon dioxide emissions by half, in the manufacturing of this material. Pex tubing is installed in the slab to create a thermal mass within the building to stabilize heating and cooling loads. Backup systems include a 12 ton chiller and a 92% efficient gas boiler, both of which exceed LEED efficient rating requirements. PEX tubing and floor insulation LEED, section – Indoor Air Quality, Section 6.1 Supply Air distribution & Section 7 Supply Air Filtering Ductless air conditioning systems like radiant floor heating (and cooling) are an alternative to these requirements. Radiant heating and cooling systems (within a concrete slab) are more efficient, create less dust and create no circulation noise. The Green Point Rated system, section H – Heating, Ventilation & Air Conditioning, item 3 This requirement calls for a zoned system, installed with Slab insulation. (One point is awarded in the Energy category, and one point in the Indoor Air Quality category Analysis 10
  11. 11. Again, it was quite difficult to research the requirements for LEED credit. Their rating system clearly addresses air duct systems, and it addresses ductless system in several different sections. GRP awarded 2 points for hydronic systems; one point for indoor air quality improvement and one point for energy savings, for amore efficient HVAC system. Renewable Energy systems (Photovoltaic System design and installation) The Canyon Barn roof is a pyramidal hip roof. The Atlantis Sun Slate integrated building panels were installed on all triangular faces of the roof, with four separate inverters for each face. Any excess electrical power generated during the day by the 4.4 KW system is returned to the PG&E electrical grid for ‘credit’ Sun Slate tiles being installed LEED, section – Energy & atmosphere, Credit 2 – On Site Renewable energy The determination for this credit under LEED is quite complex, for the average builder/homeowner, for it requires several energy cost calculations, based on different governmental databases. Based on these prior calculations, the points are then awarded based on the following percentages of the summary of renewable energy provided % Renewable Energy Points 2.5% 1 11
  12. 12. 7.5% 2 12.5% 3 The Green Point Rated system, section I – Renewable Energy, item 4 Provides successive points (in six point intervals) for the percentage of electrical needs provided by this renewable energy system a. 30 % pf electric needs OR 1.2 KW system (total 6 points) b. 60% pf electric needs OR 2.4 KW system (total 12 points) c. 90% pf electric needs OR 3.6 KW system (total 18 points) Analysis Given the weighing factor (6 vs. 18 points), the GPR point credit clearly awards more accreditation points for PV systems, in this case. The main reason being for the scaled weighing in that, electrical power in California, per KW is the forth highest in the nation, and the cost savings factor per KW is reflected in the higher California rating system credit. Secondly, California receives more annual Isolation [4] (the average daily solar amount of radiation received in an area) than more states, and renewable systems like PV systems can provide more renewable electrical environmental ‘credits’. California PV energy cost savings are somewhat difficult to determine, given the variable costs of PV panels (prices are decling based on current availability) , the state rebate sliding scale, per watt (decling as more PV systems come online), and the new federal tax credit (30% of project costs). The LEED system does not include any of these varying factors in determining the cost/benefit analysis, while the GPR system ignores these important factors in determining the true life ‘cycle cost ‘of such a system. Rainwater Harvesting (Water Catchment systems) The Canyon building rainwater catchment system collects rainwater from the 2,000 sq. ft. pyramidal hip roof . Rain calculations showed that annual rainfall for the area is 26” per year, with the roof collecting about 625 gallons in a 1’ rainfall. The rainwater catchment system was designed to hold 15,000 gallons. The annual 12
  13. 13. rainfall catchment required for LEED credit is 90% or 14,625 gallons of annual rainfall. Any excess rainwater not stored on site need to be filtered to attain an 80% sediment free discharge. 15,000 gall water catchment storage tanks LEED, section SS 6.2 – Storm water Design: Quality Control : Storm water storage has the capacity to capture 90% of the annual rainfall Amount : Any excess water runoff must have 80% of suspended solids removed The Green Point Rated system No stated criteria Analysis Any accreditation system should evaluate catchments systems with respect to such examples as • Mitigate property soil runoff, eliminating soil erosion • Mitigate excess water runoff on established rainwater runoff systems • Purify rainwater contaminants through soil filtration • Recycle water for landscape requirements • Maintain independent fire protection water reservoirs 13
  14. 14. • Build indent communities where resources are provided in part by localize d resource systems The LEED system provides clear, but detailed guidelines for stormwater catchment credit, but the GPR system does not adequately addresses this water conservation measure. This may be addressed in the next version, since California is taking more drastic measures to conserve water, in light of climate change factors effecting rainfall and snow fall in our state. The Green Building Guidelines manual mentions construction of a rainwater catchment system such as a cistern, in the Landscaping section overview, but there are no points categories for controlling rainwater runoff, or rainwater harvesting in the Checklist. Costs of Accreditation Costs associated with comparing the cost structure for the two rating systems is out side the scope of this paper, primarily because of the complexity of the LEED requirements for determining critical energy savings calculations, and the need for detailed drawings, documents and other filings that would generate another topic. The LEED certification can be in excess of $20,000, given the project scope. Build It Green costs can be below $2,500 for minimal accreditation. This is of course, a very important element in addressing which rating system to choose (in California) for new construction. The cost for the platinum rating for the Canyon building was $16,000 Other Rating Systems Green Point Rated is a comprehensive program specifically addressing the needs of California's residential building industry, but using it does not preclude participating in other green home rating systems. In fact, Green Point Rated was designed not to compete with but rather be compatible with programs such as those listed below. The LEED rating system includes some reciprocation accreditation in some rating programs, provided certain point totals are attained. National Association of Home Builders NAHB is a national, Washington, D.C.-based trade association whose mission is to enhance the climate for housing and the building industry. Chief among 14
  15. 15. NAHB’s goals is providing and expanding opportunities for all consumers to have safe, decent and affordable housing.[7] California Green Builder The program encourages voluntary partnerships between builders and local governments to build cost-effective, green homes that benefit homebuyers and the community at large. Builders who embrace CGB differentiate themselves in the marketplace through resource efficiency. Documented savings is a plus for local officials who must record greenhouse gas emissions and water conservation efforts. The California Green Builder homebuyers benefit from lower energy costs while their home makes less impact on the environment. This program was developed by the building industry for production home builders. This certification system does not cover the Renewable energy, Community or Landscaping categories of LEED and Build It Green.[8] Energy Star ENERGY STAR is a joint national program of the U.S. Environmental Protection Agency and the U.S. Department of Energy helping all homeowners save money and protect the environment through energy efficient products and practices. Third party raters verify that homes adhere to their standards for insulation, efficient windows, building envelop, HVAC and home appliances. To earn the Energy Star Rating, a home must meet guidelines for energy efficiency set by the U.S. Environmental Protection Agency. These homes are at least 15% more energy efficient than homes built to the 2004 International Residential Code, and include additional energy-saving features that typically make them 20–30% more efficient than standard homes [9]. Both rating systems analyzed promote Energy Star Lighting and Appliance products in their accreditation protocol [9]. Conclusion There are many other, possibly more important aspects that will evolve from both green building initiatives, such as LEED and GPR, which promote sustainable and earth friendly housing. Hopefully, these measures will help us restructure our ‘world view’ about our buildings, and help us to become better stewards of our environment. They 15
  16. 16. will help view our buildings as part of the world landscape, rather than abstract structures of our rational mind. They will help us to use fewer resources in building them, and to design them so their components can be reused, or recycled. I present several concepts that may help the reader to better understand how green buildings can gain a wider acceptance, by the nature of their contribution tour long term lifestyle, and build better evaluation for us all Life cycle cost models Traditionally, financial models for new home construction concentrate on the project budget, assigning separate dollars to various design and construction phases. When heating systems are evaluated, for example, the initial purchase/installation costs are too often used as the deciding choice factor. Green Building concepts help to promote a better financial model, by evaluating a home’s overall life cycle cost. This long term view allows the costs of home ownership to be understood from a wider picture, which includes the initial purchase/installation costs, but maintenance, energy costs, and the escalating utility factors in the future. Many project decisions are determined by payback models or risk/benefit analysis, but we seldom apply these models to our new home analysis. For example, solar thermal hot water systems can provide a payback period of 5-7 years for an average home, given the current state rebates tax credit incentives, and factored gas price escalation, but new home designers/buyers just view the initial purchase costs, of a traditional gas fired, hot water system as a ‘cost savings’. A long term life cycle model will reveal the true savings, and cleaner environmental aspect of such a solar thermal systems Conserve natural resources/ Reduce GHG emissions Such programs significantly offset demands for water, energy, land use and related infrastructure systems, required for home projects that do not look at their impact on existing systems. But more important are the reused, and recycled materials that do not end up in city landfills, retain existing resources like wood and water. Green House Gases can be reduced with less new materials manufactured, when recycling is employed. Many materials today are formaldehyde free, or contain very low volatile compounds, make the environment cleaner, and create better indoor air quality. Higher cost for going green myth 16
  17. 17. A major issue concerning the acceptance of sustainable homes had been the perceived ‘cost’ of going ‘green’. This perception revolves mainly around the costs of sustainable materials, which includes a variety of factors that confuse the comparison – recycled, reuse, composite, high efficiency, high tech, etc. This argument may have been more valid several years ago, but the pricing differential for traditional versus green products has continued to level out. There several studies that demonstrate that the increased ‘cost’ for new ‘green’ homes lie in the increased design costs. This cost should diminish, as this is an important tenet of both rating parties’ mission statements – to educate more manufacturers, architects and builders to green building products and construction practices. A recent panel discussion of building officials for the cities of Walnut Creek, Pleasanton, Pleasant Hill and Dublin hosted by the Northern California group for the USGBC stated that the upfront design costs average about 2-3% for new Homes (March 25, 2009 meeting in the Walnut Creek Lesher Center). This study does not even factor in the overall savings, when the new home project costs are considered in the total project life cycle model. Dual Certification “The thing I like about standards is that there are so many to choose from….” It’s a popular lament, especially among architects and builders, and recently with ‘standards’ raters/reviewers of our comparative systems. Given the wide dispersion with the LEED and GPR accreditation system scales, it is often hard to make comparisons, and to find common ground so that green components can be compared. The LEED system does award reciprocal points in the Green Rated program, if applicants achieve certain point levels in the LEED system Evolving set of guidelines These ratings are at best, the best approximation of how builders, architects and vendors can bring to the marketplace their best evaluations of the most current design, materials and building practices available. Build It Green has revised, and published their April 2009 guidelines, which were not available for this report, but I am confident will contain more updated requirements, especially in light of the various new state initiatives. The LEED program is about to start training on the 3.0 version, as well Building Industry Changes 17
  18. 18. Builder will continue to incorporate more sustainable materials in their projects, as the standards become more commonplace. This will help to encourage more manufacturers to enter this market, and encourage people to create new sustainable products, especially as the builders find that their costs to traditional building materials are comparable over time. Last words Learning about the Canyon Construction building has been an invaluable opportunity to really study all about the ways buildings can reduce their environmental impact. I am also now learning how buildings can not only minimize their site impact, but contribute to it, and help rebuild it… Also, LEED is a federal program; Build It Green is a California based initiative. I now better appreciate how easier it is to work with a state program. LEED is almost beyond comprehension, at times, with it s calculations, references to other standards requirements and verification documentation, to name a few……………... I hope to learn more…………… Thank you for a most rewarding class…… References 1. Davis Energy Group, Green Point Rated and LEED for Homes 2. LEED, New construction Reference Guide, Version 2.2, Third edition, October 2007 3. Build It Green – Green Building Guidelines, 2007 Edition 4. Grid-Tied PV System Seminar Textbook, Solar Living Institute 2007, pg89 5. 6. 7. 8. 9. ATTACHMENTS LEED for Homes Pilot Project Checklist Single Family GreenPoint Checklist 18